In order to conserve energy, builders of residential and business structures have looked increasingly to the inherent advantages of an underground structure. Such structures not only conserve energy by providing warmth in the wintertime and coolness in the summertime, but such structures minimize almost all external noise and therefore provide a nearly silent environment. Obviously, such structures provide increased protection against natural calamities, such as high wind, lightning, tornadoes, and they are more fire resistant than conventional above-ground structures. In addition, such structures are virtually maintenance free exteriorly and are impervious to termites. Further advantages of underground structures are that there is virtually no possibility of frozen water pipes with resultant damage to plumbing and plumbing fixtures, and insurance rates are markedly reduced because of the natural protection provided.
The primary reason why underground structures for both residential and business use have not become more popular is because known building techniques for such structures are too expensive. In addition to the high cost of conventional designs, there is a certain amount of reluctance to undertake building such underground structures because of a concern of collapse and deterioration under the weight of the overlying earth. Such concerns are only justified if the materials of construction are inadequate to carry the weight of the surrounding earth material, and in order to overcome these concerns, known construction techniques add considerably to the cost.
It is therefore a primary object of the invention to provide a structure that provides all of the advantages of the earth sheltered construction but which can be constructed at costs competitive with conventional above-ground structures.
The structure of the invention utilizes the principles of a suspension design for both the roof and buried walls. In the roof structure, sheets of steel are placed in an upward concave position supported by beams and columns with compression members positioned between the beams. In the walls, a similar arrangement is used with sheets of steel in a concave outward position supported between the columns. On relatively small structures, the invention provides a free span design with no columns or bearing walls inside the basic structure, and with larger buildings, multiple spans can be utilized.